Biochar is a novel carbonized feed additive sourced from pyrolyzed biomass. This compound is known to adsorb gasses and carbon, participate in biological redox reactions and provide habitat biofilms for desirable microbiota proliferation. Therefore, biochar holds potential to modify rumen fermentation characteristics and reduce enteric CH 4 emissions. The objective of this study was to investigate the effect of hardwood biochar supplementation on fermentation parameters, methane (CH 4 ) production and the ruminal archaeal, bacterial, and fungal microbiota using the in vitro RUSITEC (rumen simulation technique) system. Treatments consisted of a control diet (oaten pasture: maize silage: concentrate, 35:35:30 w/w) and hardwood biochar included at 400 or 800 mg per day (3.6 and 7.2% of substrate DM, respectively), over a 15-day period. Biochar supplementation had no effect ( P ≥ 0.37) on pH, effluent (mL/d), total gas (mL/d), dry matter (DM) digestibility or CH 4 production (mg/d). The addition of 800 mg biochar per day had the tendency ( P = 0.10) to lower the % of CH 4 released in fermentation compared to 400 mg/d biochar treatment. However, no effect ( P ≥ 0.44) was seen on total VFA, acetate, propionate, butyric, branched-chain VFA, valerate and caproate production and the ratio of acetate to propionate. No effect ( P > 0.05) was observed on bacterial, archaeal or fungal community structure. However, biochar supplementation at 800 mg/d decreased the abundance of one Methanomethylophilaceae OTU (19.8-fold, P = 0.046) and one Lactobacillus spp. OTU (31.7-fold, P < 0.01), in comparison to control treatments. Two fungal OTUs classified as Vishniacozyma victoriae (5.4 × 10 7 increase) and Sporobolomyces ruberrimus (5.4 × 10 7 -fold increase) were more abundant in the 800 mg/d biochar samples. In conclusion, hardwood biochar had no effects on ruminal fermentation characteristics and may potentially lower the concentration of enteric CH 4 when included at higher dosages by manipulating ruminal microbiota abundances.

Ensiling vegetables with forage crops is a suggested method of waste diversion and can be directly utilized as a livestock feed. Carrot or pumpkin, ensiled at 0, 20, or 40% dry matter (DM) with crop sorghum, and with or without a second-generation silage inoculant were assessed for nutritive composition, organic acid profiles, aerobic stability and in vitro rumen fermentation characteristics. The study was a completely randomized design, with the fixed effects consisting of vegetable type (carrot vs. pumpkin), level (i.e., the level of vegetables), inoculant (inoculant or non-inoculant) and the interactions, and mini-silos within treatment as the random effect. The experimental unit for sorghum treatments represented by each mini-silo (5 kg capacity). Silage was sampled after 70-days ensiling for nutrient composition, 14-day aerobic stability, organic acid profiles and microbial diversity. After 24 h in vitro incubation, rumen fermentation parameters were assessed, measuring gas and methane (CH4) production, in vitro digestibility and volatile fatty acid concentrations. Sorghum ensiled with carrot or pumpkin at 20% or 40% DM increased crude fat (P ≤ 0.01) and decreased (P ≤ 0.01) silage surface temperature upon aerobic exposure compared to the control. Bacterial communities analyzed through 16S rRNA gene sequencing linearly increased (P ≤ 0.01) in diversity across both vegetables when the vegetable proportion was increased in the silage; dominated by Lactobacillus species. ITS analysis of the fungal microbiota upon silage opening and after 14 days (aerobic stability) identified increased (P ≤ 0.03) fungal diversity with increasing vegetable proportions, predominantly populated by Fusarium denticulatum, Issatchenkia orientalis, Kazachstania humilis, and Monascus purpureus. Upon assessment in vitro, there was an increase (P ≤ 0.04) in in vitro digestibility and some CH4 parameters (% CH4, and mg CH4/g DM), with no effect (P ≥ 0.17) on remaining CH4 parameters (mL CH4/g DM, mg CH4/g digested DM), gas production or pH. However, increasing vegetable amount decreased percentage of acetic acid and increased percentage of propionic acid of the total VFA, decreasing A:P ratio and total VFA concentration as a result (P ≤ 0.01). The results from this study indicate including carrot or pumpkin at 20 or 40% DM in a sorghum silage can produce a highly digestible, microbially diverse and energy-rich livestock feed.

Context Many tree and shrub species are underestimated fodder resources due to insufficient knowledge about their potential feeding value, especially for goats. Aims The present work aimed at assessing productive and nutritional attributes of the foliage of the following four temperate tree species widespread in Europe: Acer pseudoplatanus, Fraxinus excelsior, Salix caprea and Sorbus aucuparia. Methods Leaf length and biomass, proximate composition, fatty acid profile, phenolic composition and in vitro true dry matter digestibility were determined along the vegetative season. Key results The leaf length of the four species was significantly related to leaf biomass and can be considered as a proficient proxy for estimating leaf biomass. The differences found among the species were remarkable, although weakly related to temporal changes, especially when considering fatty acid and phenolic compositions. Fraxinus excelsior sprouts were the most productive, with a mean biomass of 13.2 g dry matter (DM) per sprout at the end of the growing season. Its foliage showed also the lowest phenolic concentrations (average total extractable phenols of 11.25 g/kg DM), resulting in the highest digestibility values (average in vitro true dry matter digestibility of 56.5 g/kg DM). Digestibility of S. aucuparia was similar, but its lower polyunsaturated fatty acid concentration (average value of 62.13 g/kg DM) could reduce the interest for this species as a feeding resource for goat dairy products with healthy properties. The lower digestibility found for A. pseudoplatanus and S. caprea (average values of 43.3 and 46.2 g/kg DM, respectively) may be related to their higher phenolic concentrations (average total extractable phenols of 45.9 and 47.3 g/kg DM, respectively). Conclusions The four species could represent an appealing feedstuff for goat nutrition, due to the valuable and complementary nutritional characteristics of their foliage. Implications The use of the studied species as fodder resource may be particularly relevant during drought periods and in the late summer when herbage quality decreases, especially in terms of crude protein and fatty acid profile.

Ozone (O 3 ) is volatile, highly oxidative, and has theoretical potential to reduce ruminant enteric methanogenesis by interactions between archaea and bacteria, and substrate and oxygen. The effects of O 3 on the rumen microbiota, fermentation parameters, and CH 4 emissions were studied through in vitro fermentation using a RUSITEC apparatus with O 3 dissolved in the salivary buffer. The substrate consisted of maize silage or grain concentrates, and the treatments were (1) control (no O 3 ) and ( 2) O 3 at 0.07 ± 0.022 mg/L in the buffer. A 4-day adaptation period followed by a 6day experimental period was used for measuring gas production and composition, as well as fermentation characteristics, which included ruminal volatile fatty acids (VFA) and liquid-and solid-associated microbial communities. Ozone treatment decreased total gas production by 15.4%, most notably CH 4 production by 20.4%, and CH 4 gas concentration by 5.8%, without compromising dry matter digestibility (DMD) of either maize silage or grain concentrates. There were no significant effects of O 3 treatment on VFA production or pH. Ozone treatment reduced the relative abundance of methanogens, particularly Methanomicrobium. This study demonstrates the potential use of O 3 as a method to reduce ruminant enteric methanogenesis.

Incorporation of carrot or pumpkin at 0, 20 or 40% dry matter (DM-basis) with crop maize, with or without a silage inoculant was evaluated after 70 days ensiling for microbial community diversity, nutrient composition, and aerobic stability. Inclusion of carrots or pumpkin had a strong effect on the silage bacterial community structure but not the fungal community. Bacterial microbial richness was also reduced (P = 0.01) by increasing vegetable proportion. Inverse Simpson’s diversity increased (P = 0.04) by 18.3% with carrot maize silage as opposed to pumpkin maize silage at 20 or 40% DM. After 70 d ensiling, silage bacterial microbiota was dominated by Lactobacillus spp. and the fungal microbiota by Candida tropicalis, Kazachstania humilis and Fusarium denticulatum. After 14 d aerobic exposure, fungal diversity was not influenced (P ≥ 0.13) by vegetable type or proportion of inclusion in the silage. Inoculation of vegetable silage lowered silage surface temperatures on day-7 (P = 0.03) and day-14 (P ≤ 0.01) of aerobic stability analysis. Our findings suggest that ensiling unsalable vegetables with crop maize can successfully replace forage at 20 or 40% DM to produce a high-quality livestock feed.

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Vegetables regarded as unsalable at processing often undergo disposal into landfill, threatening food security and increasing emissions through decomposition. Ensiling vegetables with forage crops is a suggested method of waste reduction that could also double as a livestock feed. Carrot or pumpkin, ensiled at 0%, 20% or 40% DM with crop sorghum, and with or without a second-generation silage inoculant were assessed for nutritive composition, organic acid profiles, aerobic stability and in vitro rumen fermentation characteristics. Silage was sampled after 70-days ensiling for nutrient composition, 14-day aerobic stability, organic acid profiles and microbial diversity. Sorghum ensiled with carrot or pumpkin at 20% or 40% DM increased crude fat (P ≤ 0.01) and decreased (P ≤ 0.01) silage surface temperature upon aerobic exposure compared to the control. Bacterial communities analyzed through 16S rRNA gene sequencing linearly increased (P ≤ 0.01) in diversity as vegetable proportion increased in the silage; dominated by Lactobacillus species. Upon assessment in vitro, there was an increase (P ≤ 0.04) in in vitro digestibility and some CH4 parameters (% CH4, and mg CH4/g DM), with no effect (P ≥ 0.17) on remaining CH4 parameters (mL CH4/g DM, mg CH4/g DMD), gas production or pH. However, increasing vegetable proportion decreased acetic and increased propionic acid concentrations respectively, decreasing A:P ratio and total VFA as a result (P ≤ 0.01). Results from this study indicate including carrot or pumpkin at 20% or 40% DM in a sorghum silage can produce a highly digestible, microbially diverse and energy-rich livestock feed whilst acting as a method of waste diversion of considerable environmental benefit.